EP3601398B1 - Dual cure method using thermally latent tin catalysts - Google Patents

Description

The present invention relates to a method for producing an object from a building material, the building material comprising radical crosslinkable groups, NCO groups and groups with Zerewitinoff-active H atoms and the object being a three-dimensional object and / or a layer. During and / or after the production of the object, the construction material is heated to a temperature of ≥ 50 ° C. and the construction material comprises one or more special tin compounds. The invention also relates to an object produced by the method according to the invention and the use of special tin compounds in additive manufacturing processes.

Coating agents that cure through two independent processes are generally referred to as dual cure systems. The binder components contained usually have different functional groups which, under suitable conditions, generally crosslink with one another independently of one another. Customary prior art dual cure systems have radiation-curable and thermally curable groups, particularly advantageous properties being obtained when isocyanate and hydroxyl groups are used as thermally crosslinking functions. However, the disadvantage of such solutions is that the reactivity of the NCO groups and / or the presence of catalysts for the second curing mechanism limits the pot life of the coating agent.

One class of dual cure systems contains blocked isocyanates. After deblocking at a suitable temperature, the NCO groups are available for reactions with polyols. Disadvantages of using blocked isocyanates are the high viscosity typical of blocked isocyanates and the usually very high deblocking temperature.

Dual cure systems can have advantages in so-called shadow curing in coating applications and when used as adhesives. This is to be understood as the hardening mechanism which does not take place photochemically but, for example, thermally. The coating or adhesive can then cure further, even in the case of complex-shaped substrates with shading compared to an exposure lamp.

There are several main groups of dual cure technology in the paint and adhesive sector: two different radical starters (UV and thermal), UV and moisture post-curing, UV and PUR 2K curing and a cationically catalyzed UV and thermal curing. Berlac AG, for example, offers a dual cure lacquer system under the name Berlac 082.907, in which a reaction between NCO groups and OH groups is initially triggered and then subjected to UV curing.

Another conceivable application of dual cure systems is in additive manufacturing processes ("3D printing"). Processes with which Objects are built up in layers. They therefore differ significantly from other methods of manufacturing objects such as milling, drilling or machining. In the latter process, an object is processed in such a way that it receives its final geometry by removing material.

Additive manufacturing processes use different materials and process technologies to build objects up in layers. One group of additive manufacturing processes uses radically crosslinkable resins which, if necessary, obtain their ultimate strength in the object formed via a second hardening mechanism. Examples of such processes are stereolithography processes and the so-called DLP process derived therefrom.

US 2016136889 A1 discloses a method for forming a three-dimensional object from a dual-cure system containing a mixture of a first polymerizable liquid component and a second solidifiable component that is different from the first component. This is first irradiated in a 3D printing process in order to build up a solid intermediate product that contains a second solidifiable component that is supported in the framework in non-solidified and / or uncured form. Simultaneously with or after the irradiation step, the second component solidifies in the three-dimensional intermediate product in order to form the three-dimensional object.

For 3D printing, the disadvantages of conventional dual cure systems with regard to the pot life mean that an unused construction material cannot be reused or the planned construction times for a product must not exceed the pot life.

1. a) mindestens einem aliphatischen, cycloaliphatischen, araliphatischen und/oder aromatischen Polyisocyanat
2. b) mindestens einer NCO-reaktiven Verbindung
3. c) mindestens einem thermolatenten anorganischen Zinn-enthaltenden Katalysator
4. d) gegebenenfalls weiteren von c) verschiedenen Katalysatoren und/oder Aktivatoren
5. e) gegebenenfalls Füllstoffen, Pigmenten, Additiven, Verdickern, Entschäumern und/oder anderen Hilfs- und Zusatzstoffen,

wobei das Verhältnis des Gewichts des Zinns aus Komponente c) und des Gewichts der Komponente a) weniger als 3000 ppm beträgt, wenn Komponente a) ein aliphatisches Polyisocyanat ist und weniger als 95 ppm beträgt, wenn Komponente a) ein aromatisches Polyisocyanat ist und wobei als thermolatente Katalysatoren die folgenden zyklischen Zinnverbindungen eingesetzt werden:

DE 10 2009 051445 A1 discloses polyisocyanate polyadducts obtainable from

1. a) at least one aliphatic, cycloaliphatic, araliphatic and / or aromatic polyisocyanate
2. b) at least one NCO-reactive compound
3. c) at least one thermolatent inorganic tin-containing catalyst
4. d) optionally further catalysts and / or activators different from c)
5. e) where appropriate, fillers, pigments, additives, thickeners, defoamers and / or other auxiliaries and additives,

wherein the ratio of the weight of the tin from component c) and the weight of component a) is less than 3000 ppm when component a) is an aliphatic polyisocyanate and is less than 95 ppm when component a) is an aromatic polyisocyanate and where as thermolatent catalysts the following cyclic tin compounds are used:

It is an object of the present invention to overcome at least one disadvantage of the prior art, at least in part. Another object of the invention is to provide a manufacturing method in which the objects to be manufactured from a dual cure construction material can be obtained as cost-effectively and / or individualized and / or resource-saving as possible, which particularly relates to the recyclability of construction material.

According to the invention, the object is achieved by a method according to claim 1, an object according to claim 14 and a use according to claim 15. Advantageous further developments are specified in the subclaims. They can be combined in any way, unless the context clearly indicates the opposite.

wobei gilt:

• D steht für -O-, -S- oder -N(R1)-
  wobei R1 für einen gesättigten oder ungesättigten, linearen oder verzweigten, aliphatischen oder cycloaliphatischen oder einen gegebenenfalls substituierten, aromatischen oder araliphatischen Rest mit bis zu 20 Kohlenstoffatomen steht, der gegebenenfalls Heteroatome aus der Reihe Sauerstoff, Schwefel, Stickstoff enthalten kann, oder für Wasserstoff oder den Rest
  
  steht, oder R1 und L3 zusammen für -Z-L5- stehen;
• D* steht für -O- oder -S-;
• X, Y und Z stehen für gleiche oder unterschiedliche Reste ausgewählt aus Alkylenresten der Formeln -C(R2)(R3)-, -C(R2)(R3)-C(R4)(R5)- oder -C(R2)(R3)-C(R4)(R5)-C(R6)(R7)- oder ortho-Arylenresten der Formeln
  
  oder
  
  wobei R2 bis R11 unabhängig voneinander für gesättigte oder ungesättigte, lineare oder verzweigte, aliphatische oder cycloaliphatische oder gegebenenfalls substituierte, aromatische oder araliphatische Reste mit bis zu 20 Kohlenstoffatomen stehen, die gegebenenfalls Heteroatome aus der Reihe Sauerstoff, Schwefel, Stickstoff enthalten können, oder für Wasserstoff stehen;
• L1, L2 und L5 stehen unabhängig voneinander für -O-, -S-, -OC(=O)-, -OC(=S)-, -SC(=O)-, - SC(=S)-, -OS(=O)₂O-, -OS(=O)₂- oder -N(R12)-,
  wobei R12 für einen gesättigten oder ungesättigten, linearen oder verzweigten, aliphatischen oder cycloaliphatischen oder einen gegebenenfalls substituierten, aromatischen oder araliphatischen Rest mit bis zu 20 Kohlenstoffatomen steht, der gegebenenfalls Heteroatome aus der Reihe Sauerstoff, Schwefel, Stickstoff enthalten kann, oder für Wasserstoff steht;
• L3 und L4 stehen unabhängig voneinander für -OH, -SH, -OR13, -Ha1, -OC(=O)R14, -SR15, - OC(=S)R16, -OS(=O)₂OR17, -OS(=O)₂R18 oder -NR19R20, oder L3 und L4 zusammen stehen für -L1-X-D-Y-L2-,
  wobei für R13 bis R20 unabhängig voneinander für gesättigte oder ungesättigte, lineare oder verzweigte, aliphatische oder cycloaliphatische oder gegebenenfalls substituierte, aromatische oder araliphatische Reste mit bis zu 20 Kohlenstoffatomen stehen, die gegebenenfalls Heteroatome aus der Reihe Sauerstoff, Schwefel, Stickstoff enthalten können, oder für Wasserstoff stehen.

A method for producing an object from a building material, wherein the building material comprises radically crosslinkable groups, NCO groups and groups with Zerewitinoff-active H atoms and the object is a three-dimensional object and / or a layer, is characterized in that during and / or after the object has been manufactured, the construction material is heated to a temperature of ≥ 50 ° C and that the construction material comprises one or more cyclic tin compounds of the formula FI, F-II and / or F-III:

where:

• D stands for -O-, -S- or -N (R1) -
  where R1 is a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted, aromatic or araliphatic radical with up to 20 carbon atoms, which may optionally contain heteroatoms from the series oxygen, sulfur, nitrogen, or hydrogen or the rest
  
  or R1 and L3 together represent -Z-L5-;
• D * stands for -O- or -S-;
• X, Y and Z stand for identical or different radicals selected from alkylene radicals of the formulas -C (R2) (R3) -, -C (R2) (R3) -C (R4) (R5) - or -C (R2) ( R3) -C (R4) (R5) -C (R6) (R7) - or ortho-arylene radicals of the formulas
  
  or
  
  where R2 to R11 independently represent saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or optionally substituted, aromatic or araliphatic radicals with up to 20 carbon atoms, which may optionally contain heteroatoms from the series oxygen, sulfur, nitrogen, or hydrogen stand;
• L1, L2 and L5 stand independently for -O-, -S-, -OC (= O) -, -OC (= S) -, -SC (= O) -, - SC (= S) -, - OS (= O) ₂ O-, -OS (= O) ₂ - or -N (R12) -,
  where R12 stands for a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted, aromatic or araliphatic radical with up to 20 carbon atoms, which can optionally contain heteroatoms from the series oxygen, sulfur, nitrogen, or stands for hydrogen;
• L3 and L4 stand independently for -OH, -SH, -OR13, -Ha1, -OC (= O) R14, -SR15, - OC (= S) R16, -OS (= O) ₂ OR17, -OS ( = O) ₂ R18 or -NR19R20, or L3 and L4 together stand for -L1-XDY-L2-,
  where R13 to R20 independently represent saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or optionally substituted, aromatic or araliphatic radicals with up to 20 carbon atoms, which may optionally contain heteroatoms from the series oxygen, sulfur, nitrogen, or for Stand for hydrogen.

The layer obtained by the method according to the invention can contact one or more further surfaces on one side, on several sides or on neither side. Accordingly, the layer can be a coating, an adhesive bond or a self-supporting film act.

Three-dimensional objects formed by the method according to the invention can have a height of 1 mm, at least in sections, in the construction direction of its manufacturing method. Coatings and adhesive bonds obtained in this way can have thicknesses of 5 µm to 800 µm and films obtained in this way can have thicknesses of 30 µm to 500 µm.

The tin compounds of the formulas F-I, F-II and F-III have no technically meaningful catalytic activity below a certain temperature for the reaction of NCO groups with functional groups which carry Zerewitinoff-active H atoms. In particular, urethanizations and urea formations should be mentioned here. Above a certain temperature, however, the catalytic activity increases sharply. Without being limited to a theory, it is assumed that the intramolecular donor-acceptor interactions in the hypervalent tin compounds used according to the invention or the secondary products formed from the latter in the matrix are weakened at higher temperature and thus the central atom (reversibly) blocked at low temperature then is available for the catalyzed reaction. In this respect, one can speak of thermally latent catalysts. Because the NCO groups present in the building material do not react below this temperature, the building material can also be easily recycled. According to the invention, to activate the Sn catalyst, it is heated to a temperature of 50 ° C., preferably ° 65 ° C., more preferably C 80 ° C., particularly preferably 80 ° C. to 200 ° C., so that after the reaction has taken place the NCO -Groups the item is obtained. The heating can take place for a period of ≥ 1 minute, preferably 5 minutes, more preferably 10 minutes to 24 hours, preferably 8 hours, particularly preferably 4 hours.

The catalytic activity of the thermolatent catalyst in the build-up material for the process according to the invention is preferably designed in such a way that the build-up material has a pot life (defined as the time in which the viscosity of the material doubles) at 23 ° C. of> 1 h, preferably> 2 h, particularly preferably> 4 h and very particularly preferably> 6 h.

Especially in those cases in which the tin compounds of the formulas F-I, F-II and / or F-III have ligands with free OH and / or NH radicals, the catalyst can be incorporated into the product in the polyisocyanate polyaddition reaction. The particular advantage of these built-in catalysts is their greatly reduced fogging behavior.

The various production methods for the tin (IV) compounds or their tin (II) precursors to be used according to the invention are described, inter alia, in: J. Organomet. Chem. 2009 694 3184-3189 , Chem. Heterocycl. Comp. 2007 43 813-834 , Indian J. Chem. 1967 5,643-645 as well as in the literature cited therein.

The proportion by weight of the tin compounds of the formulas FI, F-II and / or F-III in the building material can be made dependent on the type of isocyanates on which the build-up material is based. Thus, if NCO groups bonded to an aromatic carbon atom dominate, the content can be 100 ppm, based on the total weight of the build-up material. If NCO groups bonded to an aliphatic carbon atom dominate, the content is 3000 ppm, based on the total weight of the building material.

The organic aliphatic, cycloaliphatic, araliphatic and / or aromatic polyisocyanates with at least two isocyanate groups per molecule and mixtures thereof, which are known per se to the person skilled in the art, are suitable as sources of NCO groups in the build-up material. For example, NCO-terminated prepolymers can be used.

As NCO-reactive compounds with Zerewitinoff-active H atoms, all compounds known to the person skilled in the art which have an average OH or NH functionality of at least 1.5 can be used. These can be, for example, low molecular weight diols (e.g. 1,2-ethanediol, 1,3- or 1,2-propanediol, 1,4-butanediol, 1,5-petanediol, 1,6-hexanediol), triols (e.g. B. glycerol, trimethylolpropane) and tetraols (e.g. pentaerythritol), short-chain amino alcohols, polyamines but also higher molecular weight polyhydroxy compounds such as polyether polyols, polyester polyols, polycarbonate polyols, polysiloxane polyols, polyamines and polyether polyamines and polybutadiene polyols.

The build-up material comprises free-radically crosslinkable groups, preferably (meth) acrylate groups. They can enter into a crosslinking reaction with one another through thermal and / or through photochemical radical initiators. The building material can therefore also be described as a radically crosslinkable building material or a radically crosslinkable resin. Furthermore, according to the definition above, it is a dual cure system.

The free-radically crosslinkable building material preferably comprises a compound which is obtainable from the reaction of an NCO-terminated polyisocyanate prepolymer with a molar deficiency of a hydroxyalkyl (meth) acrylate, based on the free NCO groups.

The free-radically crosslinkable building material likewise preferably comprises a compound which is obtainable from the reaction of an NCO-terminated polyisocyanurate with a molar deficit of a hydroxyalkyl (meth) acrylate, based on the free NCO groups.

Suitable polyisocyanates for preparing the NCO-terminated polyisocyanurates and prepolymers are, for example, those which have a molecular weight in the range from 140 to 400 g / mol, with aliphatically, cycloaliphatically, araliphatically and / or aromatically attached isocyanate groups, such as. B. 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane , 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3, 5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate; IPDI), 1-isocyanato-1-methyl-4 (3) -isocyanatomethylcyclohexane, 2, 4'- and 4,4'-diisocyanatodicyclohexylmethane (H ₁₂ MDI), 1,3- and 1,4-bis (isocyanatomethyl) cyclohexane, bis (isocyanatomethyl) norbornane (NBDI), 4,4'-diisocyanato-3 , 3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3 ', 5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanato-1,1'-bi (cyclohexyl), 4,4'-diisocyanato-3 , 3'-dimethyl-1,1'-bi (cyclohexyl), 4,4'-diisocyanato-2,2 ', 5,5'-tetra-methyl-1,1'-bi (cyclohexyl), 1,8 -Diisocyanato-p-menthane, 1,3-diisocyanato-adamantane, 1,3-dimethyl-5,7-diisocyanatoadamantane, 1,3- and 1,4-bis (isocyanatomethyl) benzene (xyxlylene diisocyanate; XDI), 1, 3- and 1,4-bis (1-isocyanato-1-methylethyl) benzene (TMXDI) and bis (4- (1-isocyanato-1-methylethyl) phenyl) carbonate, 2,4- and 2,6- Diisocyanatotoluene (TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-diisocyanatonaphthalene and any ge mixtures of such diisocyanates.

According to the invention, prepolymers bearing aliphatic and / or aromatic isocyanate end groups, such as, for example, aliphatic or aromatic isocyanate end groups, can also be used as starting materials for isocyanurate formation. Suitable trimerization catalysts are described below in connection with another embodiment.

Suitable hydroxyalkyl (meth) acrylates include alkoxyalkyl (meth) acrylates with 2 to 12 carbon atoms in the hydroxyalkyl radical. Preference is given to 2-hydroxyethyl acrylate, the mixture of isomers formed on addition of propylene oxide onto acrylic acid, or 4-hydroxybutyl acrylate.

The reaction between the hydroxyalkyl (meth) acrylate and the NCO-terminated polyisocyanurate can be catalyzed by the usual urethanization catalysts such as DBTL. In this reaction, the molar ratio between NCO groups and OH groups of the hydroxyalkyl (meth) acrylate can be in a range from ≥10: 1 to ≤ 1.1: 1 (preferably ≥ 5: 1 to ≤ 1.5: 1, more preferably 4: 1 to 2: 1). The curable compound obtained can have a number average molecular weight M _n of ≥ 200 g / mol to 5000 g / mol. This molecular weight is preferably 300 g / mol to 4000 g / mol, more preferably 400 g / mol to 3000 g / mol.

Particularly preferred is a curable compound obtained from the reaction of an NCO-terminated polyisocyanurate with hydroxethyl (meth) acrylate, the NCO-terminated polyisocyanurate being obtained from 1,6-hexamethylene diisocyanate in the presence of an isocyanate trimerization catalyst. This curable compound has a number average molecular weight M _n of ≥ 400 g / mol to 3000 g / mol and a molar ratio of NCO groups and olefinic C = C double bonds in a range from 1: 5 to 5: 1. particularly preferably 1: 3 to 3: 1, very particularly preferably. ≥1: 2 to ≤ 2: 1.

The free-radically crosslinkable building material can furthermore contain additives such as fillers, UV stabilizers, free radical inhibitors, antioxidants, mold release agents, water scavengers, slip additives, defoamers, leveling agents, rheology additives, flame retardants and / or pigments. These auxiliaries and additives, with the exception of fillers and flame retardants, are usually in an amount of less than 50% by weight, preferably less than 30% by weight, particularly preferably up to 20% by weight, particularly preferably up to 10% by weight .-%, based on the radically crosslinkable resin. Flame retardants are usually present in amounts of not more than 70% by weight, preferably not more than 50% by weight, particularly preferably not more than 30% by weight, calculated as the total amount of flame retardants used based on the total weight of the free-radically crosslinkable builder material.

Suitable fillers are, for example, AlOH ₃ , CaCO ₃ , cut glass fibers, carbon fibers, polymer fibers, metal pigments such as TiO ₂ and other known customary fillers. These fillers are preferably used in amounts of not more than 70% by weight, preferably not more than 50% by weight, particularly preferably not more than 30% by weight, calculated as the total amount of fillers used based on the total weight of the free-radically crosslinkable resin.

Suitable UV stabilizers can preferably be selected from the group consisting of piperidine derivatives, such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-1,2,2,6,6-pentamethylpiperidine, bis (2,2,6,6-tetra-methyl-4-piperidyl) -sebacate, bis (1,2,2,6,6-pentamethyl-1-4-piperidinyl) -sebacate, bis- (2,2, 6,6-tetrainethyl-4-piperidyl) suberate, bis (2,2,6,6-tetramethyl-4-piperidyl) dodecanedioate; Benzophenone derivatives, such as, for example, 2,4-dihydroxy-, 2-hydroxy-4-methoxy-, 2-hydroxy-4-octoxy-, 2-hydroxy-4-dodecyloxy- or 2,2'-dihydroxy-4-dodecyloxy-benzophenone ; Benzotriazole derivatives such as 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol, 2- (2H -Benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (5-chloro-2H-benzotriazol-2-yl) -6- (1,1-dimethylethyl) - 4-methylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3 -tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -6- (1-methyl- 1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol, isooctyl 3- (3 - (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxyphenyl propionate ), 2- (2H-benzotriazol-2-yl) -4,6-bis (1,1-dimethylethyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl- 1-phenylethyl) phenol, 2- (5-chloro-2H-benzotriazol-2-yl) -4,6-bis (1,1-dimethylethyl) phenol; Oxalanilides, such as, for example, 2-ethyl-2'-ethoxy- or 4-methyl-4'-methoxyoxalanilide; Salicylic acid esters, such as, for example, salicylic acid phenyl ester, salicylic acid 4-tert-butylphenyl ester, salicylic acid 4-tert-octylphenyl ester; Cinnamic acid ester derivatives, such as, for example, α-cyano-β-methyl-4-methoxycinnamate, alpha-cyano-beta-methyl-4-methoxycinnamate, ethyl alpha-cyano-beta-phenylcinnamate, isooctyl alpha-cyano-beta-phenylcinnamate; and malonic ester derivatives such as dimethyl 4-methoxybenzylidene malonate, diethyl 4-methoxybenzylidene malonate, dimethyl 4-butoxybenzylidene malonate. These preferred light stabilizers can be used either individually or in any combination with one another.

Particularly preferred UV stabilizers are those which completely absorb radiation of a wavelength <400 nm. These include, for example, the benzotriazole derivatives mentioned. Very particularly preferred UV stabilizers are 2- (5-chloro-2H-benzotriazol-2-yl) -6- (1,1-dimethylethyl) -4-methylphenol, 2- (2H-benzotriazol-2-yl) -4 - (1,1,3,3-tetramethylbutyl) phenol and / or 2- (5-chloro-2H-benzotriazol-2-yl) -4,6-bis (1,1-dimethylethyl) phenol.

Optionally, one or more of the UV stabilizers mentioned by way of example are added to the free-radically crosslinkable builder material, preferably in amounts of 0.001 to 3.0% by weight, particularly preferably 0.005 to 2% by weight, calculated as the total amount of UV stabilizers used, based on the Total weight of the free-radically crosslinkable building material, added.

Suitable antioxidants are preferably sterically hindered phenols, which can preferably be selected from the group consisting of 2,6-di-tert-butyl-4-methylphenol (Ionol), pentaerythritol tetrakis (3- (3,5-di-tert butyl-4-hydroxyphenyl) propionate), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol bis (3-tert-butyl-4-hydroxy -5-methylphenyl) propionate, 2,2'-thio-bis (4-methyl-6-tert-butylphenol) and 2,2'-thiodiethyl-bis [3- (3,5-di-tert-butyl-4 hydroxyphenyl) propionate]. If required, these can be used individually or in any combination with one another. These antioxidants are preferably used in amounts of 0.01 to 3.0% by weight, particularly preferably 0.02 to 2.0% by weight, calculated as the total amount of antioxidants used based on the total weight of the free-radically crosslinkable builder material.

Suitable free radical inhibitors or retarders are particularly those which specifically inhibit uncontrolled free radical polymerization of the resin formulation outside the desired (irradiated) area. These are decisive for good edge definition and imaging accuracy in the forerunner. Suitable radical inhibitors must be selected according to the desired radical yield from the irradiation / exposure step and the rate of polymerization and reactivity / selectivity of the double bond carriers. Suitable radical inhibitors are, for. B. 2,2- (2,5-thiophencliyl) bis (5-tertbutylbenzoxazole), phenothiazine, hydroquinones, hydroquinone ethers, quinone alkyds and nitroxyl compounds and mixtures thereof, benzoquinones, copper salts, catechols, cresols, nitrobenzene and oxygen. These antioxidants are preferably used in amounts of 0.001% by weight to 3% by weight.

The molar concentration of Zerewitinoff-active H atoms in relation to free isocyanates is preferably ≥ 0.6 and ≤ 1.5, preferably ≥ 0.8 and ≤ 1.4, particularly preferably ≥ 0.9 and ≤ 1, 3, and very particularly preferably ≥ 1 and ≤ 1.2.

1. I) Abscheiden von radikalisch vernetztem Aufbaumaterial auf einem Träger, so dass eine Lage eines mit dem Träger verbundenen Aufbaumaterials erhalten wird, welche einem ersten ausgewählten Querschnitt des Vorläufers entspricht;
2. II) Abscheiden von radikalisch vernetztem Aufbaumaterial auf eine zuvor aufgetragene Lage des Aufbaumaterials, so dass eine weitere Lage des Aufbaumaterials erhalten wird, welche einem weiteren ausgewählten Querschnitt des Vorläufers entspricht und welche mit der zuvor aufgetragenen Lage verbunden ist;
3. III) Wiederholen des Schritts II), bis der Vorläufer gebildet ist;
   wobei das Abscheiden von radikalisch vernetztem Aufbaumaterial wenigstens in Schritt II) durch Belichten und/oder Bestrahlen eines ausgewählten Bereichs eines radikalisch vernetzbaren Aufbaumaterials, entsprechend dem jeweils ausgewählten Querschnitt des Vorläufers, erfolgt und wobei das radikalisch vernetzbare Aufbaumaterial eine Viskosität (23 °C, DIN EN ISO 2884-1) von ≥ 5 mPas bis ≤ 1000000 mPas aufweist,
   wobei das radikalisch vernetzbare Aufbaumaterial eine härtbare Komponente umfasst, in der NCO-Gruppen und olefinische C=C-Doppelbindungen vorliegen und nach Schritt III) weiterhin Schritt IV) durchgeführt wird:
4. IV) Erwärmen des nach Schritt III) erhaltenen Vorläufers auf eine Temperatur von ≥ 50 °C, so dass der Gegenstand erhalten wird.

In a preferred embodiment, the object is a three-dimensional object, the object is obtained from a precursor and the method comprises the steps:

1. I) depositing radically crosslinked building material on a carrier, so that a layer of a building material connected to the carrier is obtained which corresponds to a first selected cross section of the precursor;
2. II) depositing radically cross-linked building material on a previously applied layer of the building material, so that a further layer of the building material is obtained which corresponds to a further selected cross section of the precursor and which is connected to the previously applied layer;
3. III) repeating step II) until the precursor is formed;
   wherein the deposition of radically crosslinked building material at least in step II) by exposure and / or irradiation of a selected area of a radically crosslinkable building material, corresponding to the selected cross-section of the precursor, and wherein the radically crosslinkable building material has a viscosity (23 ° C, DIN EN ISO 2884-1) of ≥ 5 mPas to ≤ 1,000,000 mPas,
   wherein the free-radically crosslinkable build-up material comprises a curable component in which NCO groups and olefinic C DoppelC double bonds are present and after step III), step IV) is also carried out:
4. IV) heating the precursor obtained in step III) to a temperature of 50 50 ° C., so that the object is obtained.

In this variant, the object is thus obtained by means of an additive manufacturing process and in two manufacturing stages. The first manufacturing stage can be viewed as a build-up stage. This construction section can be implemented by means of optical additive manufacturing processes such as the inkjet process, stereolithography or the DLP (digital light processing) process and is the subject of steps I), II) and III). The second production stage can be regarded as a hardening stage and is the subject of step IV). Here, the precursor or intermediate object obtained after the construction section is converted into a mechanically more durable object without further changing its shape.

In step I) of this variant of the process, a radically crosslinked one is deposited Building material on a carrier. This is usually the first step in inkjet, stereolithography, and DLP processes. In this way, a layer of a building material connected to the carrier is obtained which corresponds to a first selected cross section of the precursor.

According to the instruction of step III), step II) is repeated until the desired precursor is formed. In step II), a radically crosslinked building material is deposited onto a previously applied layer of the building material, so that a further layer of the building material is obtained which corresponds to a further selected cross section of the precursor and which is connected to the previously applied layer. The previously applied layer of the building material can be the first layer from step I) or a layer from a previous run of step II).

It is provided in this variant of the method that the deposition of a radically crosslinked building material takes place at least in step II) (preferably also in step I) by exposure and / or irradiation of a selected area of a radically crosslinkable resin, corresponding to the selected cross section of the object. This can be done both by selective exposure (stereolithography, DLP) of the cross-linkable build-up material and also by selective application of the cross-linkable build-up material, followed by an exposure step that no longer needs to be selective due to the previous selective application of the cross-linkable build-up material (inkjet process).

In the context of this invention, the terms "radically crosslinkable building material" and "radically crosslinked building material" are used. In this case, the radically crosslinkable building material is converted into the radically crosslinked building material by exposure and / or irradiation, which triggers free radical crosslinking reactions. "Exposure" is understood here to mean the action of light in the range between near IR and near UV light (1400 nm to 315 nm wavelength). The other shorter wavelength ranges are covered by the term "irradiation", for example far UV light, X-rays, gamma rays and also electron rays.

The respective cross-section is expediently selected using a CAD program with which a model of the object to be manufactured was generated. This operation is also called "slicing" and serves as the basis for controlling the exposure and / or irradiation of the radically crosslinkable resin.

In this process variant, the free-radically crosslinkable build-up material has a viscosity (23 ° C., DIN EN ISO 2884-1) of 5 5 mPas to 100 1,000,000 mPas. It is therefore to be regarded as a liquid resin, at least for the purposes of additive manufacturing. The viscosity is preferably 50 mPas to 100,000 mPas, more preferably 500 mPas to 50,000 mPas.

Furthermore, in the process, the resin which can be crosslinked by free radicals comprises a curable component in which NCO groups and olefinic C CC double bonds are present. In this curable component, the molar ratio of NCO groups and olefinic C =C double bonds can be in a range from 1: 5 to 5: 1 (preferably 1: 4 to 4: 1, more preferably 1: 3 up to ≤ 3: 1). The molecular ratio of these functional groups can be determined by integrating the signals of a sample in the ¹³ C-NMR spectrum.

In addition to the curable component, the free-radically crosslinkable building material can also comprise a non-curable component in which, for example, stabilizers, fillers and the like are combined. In the curable component, the NCO groups and the olefinic C =C double bonds can be present in separate molecules and / or in a common molecule. If NCO groups and olefinic C =C double bonds are present in separate molecules, the body obtained after step IV) of this process variant can have an interpenetrating polymer network

In this variant of the method, step IV) is still carried out after step III). In this step, the precursor obtained in step III) is heated to a temperature of 50 ° C., preferably ° 65 ° C., more preferably 80 ° C., particularly preferably 80 ° C. to 200 ° C., so that the Object is obtained. The heating can take place for a period of ≥ 1 minute, preferably 5 minutes, more preferably 10 minutes to 24 hours, preferably 8 hours, particularly preferably 4 hours.

The reaction is preferably carried out until 30%, preferably 20% and more preferably 15% of the NCO groups originally present are still present. This can be determined using quantitative IR spectroscopy.

It is preferred that step IV) is only carried out when all of the build-up material of the precursor has reached its gel point. The gel point is considered to have been reached when, in a dynamic mechanical analysis (DMA) with a plate / plate oscillation viscometer according to ISO 6721-10 at 20 ° C., the graphs of the storage modulus G 'and the loss modulus G "cross Precursors exposed to further exposure and / or irradiation to complete the radical crosslinking. The radical crosslinked building material can have a storage modulus G '(DMA, plate / plate oscillation viscometer according to ISO 6721-10 at 20 ° C and a shear rate of 1 / s) of ≥ 10 ⁶ Pa.

• der Träger ist innerhalb eines Behälters angeordnet und ist vertikal in Schwerkraftrichtung absenkbar,
• der Behälter enthält das radikalisch vernetzbare Aufbaumaterial in einer Menge, welche ausreicht, um wenigstens den Träger und eine in vertikaler Richtung gesehenen obersten Oberfläche von auf dem Träger abgeschiedenem vernetztem Aufbaumaterial zu bedecken,

• vor jedem Schritt II) wird der Träger um eine vorbestimmte Strecke abgesenkt, so dass über der in vertikaler Richtung gesehen obersten Lage des vernetzten Aufbaumaterials sich eine Schicht des radikalisch vernetzbaren Aufbaumaterials bildet und
• in Schritt II) belichtet und/oder bestrahlt ein Energiestrahl den ausgewählten Bereich der Schicht des radikalisch vernetzbaren Aufbaumaterials, entsprechend dem jeweils ausgewählten Querschnitt des Vorläufers.

In a further preferred embodiment, the method has the features:

• the carrier is arranged inside a container and can be lowered vertically in the direction of gravity,
• the container contains the free-radically crosslinkable building material in an amount which sufficient to cover at least the carrier and an uppermost surface, viewed in the vertical direction, of crosslinked building material deposited on the carrier,

• before each step II), the carrier is lowered by a predetermined distance, so that a layer of the radically crosslinkable construction material is formed over the topmost layer of the crosslinked building material, as seen in the vertical direction
• in step II), an energy beam exposes and / or irradiates the selected area of the layer of the radically crosslinkable building material, corresponding to the respectively selected cross section of the precursor.

Thus, according to this embodiment, the additive manufacturing process of stereolithography (SLA) is covered. The carrier can, for example, be lowered by a predetermined distance of 1 1 μm to 2000 μm.

• der Träger ist innerhalb eines Behälters angeordnet ist und vertikal entgegen der Schwerkraftrichtung anhebbar,
• der Behälter stellt das radikalisch vernetzbare Aufbaumaterial bereit,
• vor jedem Schritt II) wird der Träger um eine vorbestimmte Strecke angehoben, so dass unter der in vertikaler Richtung gesehen untersten Lage des vernetzten Aufbaumaterials sich eine Schicht des radikalisch vernetzbaren Aufbaumaterials bildet und
• in Schritt II) belichtet und/oder bestrahlt eine Mehrzahl von Energiestrahlen den ausgewählten Bereich der Schicht des radikalisch vernetzbaren Aufbaumaterials, entsprechend dem jeweils ausgewählten Querschnitt des Vorläufers, gleichzeitig.

In a further preferred embodiment, the method has the features:

• the carrier is arranged inside a container and can be lifted vertically against the direction of gravity,
• the container provides the radically crosslinkable building material,
• before each step II), the carrier is raised by a predetermined distance so that a layer of the radically crosslinkable construction material is formed under the lowest layer of the crosslinked building material seen in the vertical direction and
• in step II), a plurality of energy beams simultaneously exposes and / or irradiates the selected area of the layer of the radically crosslinkable building material, corresponding to the respectively selected cross section of the precursor.

Thus, according to this embodiment, the additive manufacturing method of DLP technology is covered when the plurality of energy beams generate the image to be provided by exposure and / or irradiation via an array of individually controllable micromirrors. The carrier can be raised, for example, by a predetermined distance of ≥ 1 µm to ≤ 2000 µm.

• in Schritt II) wird das radikalisch vernetzbare Aufbaumaterial aus einem oder mehreren Druckköpfen, entsprechend dem jeweils ausgewählten Querschnitt des Vorläufers, aufgetragen und wird anschließend belichtet und/oder bestrahlt.

In a further preferred embodiment, the method has the features:

• in step II) the free-radically crosslinkable building material is applied from one or more print heads, corresponding to the respectively selected cross section of the precursor, and is then exposed and / or irradiated.

Thus, according to this embodiment, the additive manufacturing process of the inkjet method is covered: the crosslinkable build-up material is optionally applied selectively by one or more print heads separately from the catalysts according to the invention the subsequent curing by irradiation and / or exposure can be unselective, for example by a UV lamp. The printhead or printheads for applying the crosslinkable building material can be a (modified) printhead for inkjet printing processes. The carrier can be designed to be movable away from the print head or the print head can be designed to be movable away from the carrier. The increments of the spacing movements between the carrier and the print head can, for example, be in a range from 1 μm to 2000 μm.

• Auftragen des Aufbaumaterials auf ein Substrat
• Einwirken von Wärme und/oder UV-Strahlung auf das aufgetragene Aufbaumaterial, so dass im aufgetragenen Aufbaumaterial eine zumindest teilweise Vernetzung der radikalisch vernetzbaren Gruppen erfolgt
• Erwärmen des aufgetragenen Aufbaumaterials auf eine Temperatur von ≥ 50 °C, so dass im aufgetragenen Aufbaumaterial zumindest teilweise eine Reaktion zwischen NCO-Gruppen und Gruppen mit Zerewitinoff-aktiven H-Atomen erfolgt.

In a further preferred embodiment, the object is a coating and the method comprises the steps:

• Applying the building material to a substrate
• The action of heat and / or UV radiation on the applied building material, so that in the applied building material an at least partial crosslinking of the radical crosslinkable groups takes place
• Heating the applied build-up material to a temperature of ≥ 50 ° C., so that in the applied build-up material there is at least a partial reaction between NCO groups and groups with Zerewitinoff-active H atoms.

The action of heat can, for example, lead to the thermal decomposition of peroxide-based radical starters. The action of UV radiation takes place by means of UV light (1400 nm to 315 nm wavelength) and activates photochemical radical initiators. In a further step, the latent Sn urethanization catalyst is activated in order to allow the second hardening mechanism to take place.

• Auftragen des Aufbaumaterials auf ein erstes Substrat
• Kontaktieren des aufgetragenen Aufbaumaterials mit einem zweiten Substrat
• Einwirken von Wärme und/oder UV-Strahlung auf das aufgetragene Aufbaumaterial, so dass im aufgetragenen Aufbaumaterial eine zumindest teilweise Vernetzung der radikalisch vernetzbaren Gruppen erfolgt
• Erwärmen des aufgetragenen Aufbaumaterials auf eine Temperatur von ≥ 50 °C, so dass im aufgetragenen Aufbaumaterial zumindest teilweise eine Reaktion zwischen NCO-Gruppen und Gruppen mit Zerewitinoff-aktiven H-Atomen erfolgt.

In a further preferred embodiment, the object is an adhesive connection and the method comprises the steps:

• Applying the building material to a first substrate
• Contacting the applied building material with a second substrate
• The action of heat and / or UV radiation on the applied building material, so that in the applied building material an at least partial crosslinking of the radical crosslinkable groups takes place
• Heating the applied build-up material to a temperature of ≥ 50 ° C., so that in the applied build-up material there is at least a partial reaction between NCO groups and groups with Zerewitinoff-active H atoms.

The action of heat can, for example, lead to the thermal decomposition of peroxide-based radical starters. The action of UV radiation takes place by means of UV light (1400 nm to 315 nm wavelength) and activates photochemical radical initiators. In a further step, the latent Sn urethanization catalyst is activated in order to allow the second hardening mechanism to take place.

In a further preferred embodiment, the build-up material furthermore comprises a free radical initiator and / or an isocyanate trimerization catalyst. In order to prevent an undesired increase in the viscosity of the free-radically crosslinkable builder material, free radical initiators and / or isocyanate trimerization catalysts can only be added to the builder material immediately before the start of the process according to the invention.

Thermal and / or photochemical free-radical initiators (photoinitiators) can be used as free-radical initiators. It is also possible that thermal and photochemical radical initiators are used at the same time. Suitable thermal radical initiators are, for example, (AIBN), dibenzoyl peroxide (DBPO), di-tert-butyl peroxide, dicumyl peroxide and / or inorganic peroxides such as peroxodisulfates.

A basic distinction is made between two types of photoinitiators, the unimolecular type (I) and the bimolecular type (II). Suitable type (I) systems are aromatic ketone compounds, such as. B. Benzophenones in combination with tertiary amines, alkylbenzophenones, 4,4'-bis (dimethylamino) benzophenone (Michler's ketone), anthrone and halogenated benzophenones or mixtures of the types mentioned. Type (II) initiators such as benzoin and its derivatives, benzil ketals, acylphosphine oxides, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxides, phenylglyoxylic acid esters, camphorquinone, α-aminoalkylphenones, α, α-dialkoxyacetophenones and α-hydroxyalkylphenones are also suitable. Specific examples are Irgacur®500 (a mixture of benzophenone and (1-hydroxycyclohexyl) phenyl ketone, from Ciba, Lampertheim, DE), Irgacure®819 DW (phenylbis- (2,4,6-trimethylbenzoyl) phosphine oxide, from Ciba, Lampertheim, DE) or Esacure® KIP EM (Oligo- [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) -phenyl] -propanone], from Lamberti, Aldizzate, Italy) and Bis- ( 4-methoxybenzoyl) diethylgerman. Mixtures of these compounds can also be used.

In the case of photoinitiators, care should be taken to ensure that they have sufficient reactivity to the radiation source used. A wide variety of photoinitiators are known on the market. Commercially available photoinitiators cover the wavelength range in the entire UV-VIS spectrum. Photoinitiators are used in the production of paints, printing inks and adhesives as well as in the dental sector.

In this variant of the process, the photoinitiator is generally used in a concentration of 0.01 to 6.0% by weight, preferably 0.05 to 4.0% by weight, based on the amount of the curable component carrying olefinically unsaturated double bonds used especially preferably from 0.1 to 3.0% by weight are used.

In a further preferred embodiment, the build-up material is obtained from the mixing of a component containing NCO groups and a component containing groups with Zerewitinoff-active H atoms, and the mixing takes place 5 5 minutes before the start of the process. In methods such as DLP methods, it is further preferred that the mixture of the building material is generated continuously and fed to the building process. In order to avoid undesired side reactions, the other constituents of the build-up material can be present in the component containing Zerewitinoff-active H atoms.

In a further preferred embodiment, in the definition according to the above statements, D is —N (R1) - and R1 is hydrogen or an alkyl, aralkyl, alkaryl or aryl radical with up to 20 carbon atoms or the radical

und Propyl-, Butyl-, Hexyl-, und Octyl stehen für alle isomeren Propyl-, Butyl-, Hexyl- sowie Octylreste.In a further preferred embodiment, in the definition according to the above statements, R1 is hydrogen or a methyl, ethyl, propyl, butyl, hexyl, octyl, _{Ph or CH 3} Ph radical or the radical

and propyl, butyl, hexyl and octyl stand for all isomeric propyl, butyl, hexyl and octyl radicals.

In a further preferred embodiment, in the definition according to the preceding statements, D * is -O-.

Further preferred features for the tin compounds according to the above are listed below:
X, Y and Z are preferably the alkylene radicals -C (R2) (R3), -C (R2) (R3) -C (R4) (R5) - or the ortho-arylene radical

Preferably, R2 to R7 are hydrogen or alkyl, aralkyl, alkaryl or aryl radicals with up to 20 carbon atoms, particularly preferably hydrogen or alkyl, aralkyl, alkaryl or aryl radicals with up to 8 carbon atoms. Atoms, very particularly preferably around hydrogen or alkyl radicals with up to 8 carbon atoms, even more preferably around hydrogen or methyl.

R8 to R11 are preferably hydrogen or alkyl radicals with up to 8 carbon atoms, particularly preferably hydrogen or methyl.

L1, L2 and L5 are preferably -NR12-, -S-, -SC (= S) -, -SC (= O) -, -OC (= S) -, -O-, or -OC (= O) -, particularly preferably around -O-, or -OC (= O) -.

R12 is preferably hydrogen or an alkyl, aralkyl, alkaryl or aryl radical with up to 20 carbon atoms, particularly preferably hydrogen or an alkyl, aralkyl, alkaryl or aryl radical with up to 12 carbon atoms Atoms, very particularly preferably hydrogen or a methyl, ethyl, propyl, butyl, hexyl or octyl radical, with propyl, butyl, hexyl and octyl for all isomeric propyl, butyl, hexyl - as well as octyl residues.

L3 and L4 are preferably -Hal, -OH, -SH, -OR13, -OC (= O) R14, the radicals R13 and R14 having up to 20 carbon atoms, preferably up to 12 carbon atoms.

L3 and L4 are particularly preferably Cl-, MeO-, EtO-, PrO-, BuO-, HexO-, OctO-, PhO-, formate, acetate, propanoate, butanoate, pentanoate, hexanoate, octanoate, laurate, Lactate or benzoate, where Pr, Bu, Hex and Oct stand for all isomeric propyl, butyl, hexyl and octyl radicals, even more preferably Cl, MeO, EtO, PrO, BuO, HexO, OctO -, PhO, hexanoate, laurate, or benzoate, where Pr, Bu, Hex and Oct stand for all isomeric propyl, butyl, hexyl and octyl radicals.

R15 to R20 are preferably hydrogen or alkyl, aralkyl, alkaryl or aryl radicals with up to 20 carbon atoms, particularly preferably hydrogen or alkyl, aralkyl, alkaryl or aryl radicals with up to 12 carbon atoms Atoms, very particularly preferably around hydrogen, methyl, ethyl, propyl, butyl, hexyl, or octyl radicals, with propyl, butyl, hexyl and octyl for all isomeric propyl, butyl, hexyl - as well as octyl residues.

The units Ll-X, L2-Y and L5-Z preferably stand for -CH ₂ CH ₂ O-, -CH ₂ CH (Me) O-, -CH (Me) CH ₂ O-, -CH ₂ C (Me ) ₂ O-, -C (Me) ₂ CH ₂ O- or -CH ₂ C (= O) O-.

oder

The unit L1-XDY-L2 preferably stands for: HN [CH ₂ CH ₂ O-] ₂ , HN [CH ₂ CH (Me) O-] ₂ , HN [CH ₂ CH (Me) O -] [CH (Me ) CH ₂ O-], HN [CH ₂ C (Me) ₂ O-] ₂ , HN [CH ₂ C (Me) ₂ O-] [C (Me) ₂ CH ₂ O-], HN [CH ₂ C (= O) O-] _2, MeN [CH ₂ CH ₂ O-] _2, MeN [CH ₂ CH (Me) O-] _2, MeN [CH ₂ CH (Me) O] [CH (Me) CH ₂ O-], MeN [CH ₂ C (Me) ₂ O-] ₂ , MeN [CH ₂ C (Me) ₂ O-] [C (Me) ₂ CH ₂ O-], MeN [CH ₂ C (= O) O-] ₂ , EtN [CH ₂ CH ₂ O-] ₂ , EtN [CH ₂ CH (Me) O-] ₂ , EtN [CH ₂ CH (Me) O-] [CH (Me) CH ₂ O -], EtN [CH ₂ C (Me) ₂ O-] ₂ , EtN [CH ₂ C (Me) ₂ O -] [C (Me) ₂ CH ₂ O-], EtN [CH ₂ C (= O) O-] ₂ , PrN [CH ₂ CH ₂ O-] ₂ , PrN [CH ₂ CH (Me) O-] ₂ , PrN [CH ₂ CH (Me) O -] [CH (Me) CH ₂ O-] , PrN [CH ₂ C (Me) ₂ O-] ₂ , PrN [CH ₂ C (Me) ₂ O -] [C (Me) ₂ CH ₂ O-], PrN [CH ₂ C (= O) O- ] ₂ , BuN [CH ₂ CH ₂ O-] ₂ , BuN [CH ₂ CH (Me) O-] ₂ , BuN [CH ₂ CH (Me) O-] [CH (Me) CH ₂ O-], BuN [CH ₂ C (Me) ₂ O-] _2, buN [CH ₂ C (Me) ₂ O -] [C (Me) ₂ CH ₂ O-], buN [CH ₂ C (= O) O-] ₂ , HexN [CH ₂ CH ₂ O-] ₂ , HexN [CH ₂ CH (Me) O-] ₂ , HexN [CH ₂ CH (Me) O-] [CH (Me) CH ₂ O-], HexN [CH ₂ C (Me) ₂ O-] ₂ , HexN [CH ₂ C (Me) ₂ O-] [C (Me) ₂ CH ₂ O-], HexN [CH ₂ C (= O) O-] ₂ , OctN [CH ₂ CH ₂ O-] ₂ , OctN [CH ₂ CH (Me) O-] ₂ , OCTN [CH ₂ CH (Me) O -] [CH (Me) CH ₂ O-], OCTN [CH ₂ C (Me) ₂ O-] _2, OCTN [CH ₂ C (Me) ₂ O -] [C (Me) ₂ CH ₂ O-], OctN [CH ₂ C (= O) O-] ₂ , where Pr, Bu, Hex and Oct can stand for all isomeric propyl, butyl and octyl radicals, PhN [CH ₂ CH ₂ O-] ₂ , PhN [CH ₂ CH (Me) O-] ₂ , PhN [CH ₂ CH (Me) O-] [CH (Me) CH ₂ O-], PhN [CH ₂ C (Me) ₂ O-] ₂ , PhN [CH ₂ C (Me) ₂ O -] [C (Me) ₂ CH ₂ O-], PhN [CH ₂ C (= O) O-] ₂ ,

or

mit n > 1(vgl. Formel F-II). Bei niedrigen Oligomerisierungsgraden findet man häufig cyclische, bei höheren Oligomerisierungsgraden lineare Oligomere mit OH- bzw. SH-Endgruppen (vgl. Formel F-III).The tin compounds - as is known to the person skilled in the art - tend to oligomerize, so that polynuclear tin compounds or mixtures of mononuclear and polynuclear tin compounds are often present. In the polynuclear tin compounds, the tin atoms are preferably connected to one another via oxygen atoms ("oxygen bridges", vide intra). Typical oligomeric complexes (polynuclear tin compounds) are formed, for example, by condensation of the tin atoms over oxygen or sulfur, e.g.

with n> 1 (see formula F-II). With low degrees of oligomerization, cyclic oligomers are often found, with higher degrees of oligomerization, linear oligomers with OH or SH end groups (cf. formula F-III).

• 1,1-Di-"R"-5-"organyl"-5-aza-2,8-dioxa-1-stanna-cyclooctane,
• 1,1-Di-"R"-5-(N-"organyl")aza-3,7-di-"organyl"-2,8-dioxa-1-stanna-cyclooctane,
• 1,1-Di-"R"-5-(N-"organyl")aza-3,3,7,7-tetra-"organyl"-2,8-dioxa-1-stanna-cyclooctane,
• 4,12-Di-"organyl"-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 4,12-Di-"organyl"-2,6,10,14-tetra-"organyl"-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7]pentadecan,
• 4,12-Di-"organyl"-2,2,6,6,10,10,14,14-octa-"organyl"-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7]pentadecan,
• wobei "R" für D*, L3 oder L4, wie oben definiert, steht und "organyl" für R1, wie oben definiert, steht.

In a further preferred embodiment, the cyclic tin compound is selected from the group of mono- or polycyclic tin compounds of the type:

• 1,1-di- "R" -5- "organyl" -5-aza-2,8-dioxa-1-stanna-cyclooctane,
• 1,1-di- "R" -5- (N- "organyl") aza-3,7-di- "organyl" -2,8-dioxa-1-stanna-cyclooctane,
• 1,1-Di- "R" -5- (N- "organyl") aza-3,3,7,7-tetra- "organyl" -2,8-dioxa-1-stanna-cyclooctane,
• 4,12-di- "organyl" -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-di- "organyl" -2,6,10,14-tetra- "organyl" -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-di- "organyl" -2,2,6,6,10,10,14,14-octa- "organyl" -1,7,9,15-tetraoxa-4,12-diaza-8- stannaspiro [7.7] pentadecane,
• where "R" stands for D *, L3 or L4, as defined above, and "organyl" stands for R1, as defined above.

• 4,12-Di-n-butyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 4,12-Di-n-butyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7]pentadecan,
• 2,4,6,10,12,14-Hexamethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 4,12-Di-n-octyl-2,6,10,14-tetramethyl-1,7,9,15 -tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 4,12-Di-n-octyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 4,12-Dimethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecan,
• 1,1-Dichloro-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctan,
• 1,1-Diisopropyl-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctan,
• 1,1-Dibenzoyl-3,3,7,7-tetramethyl 5-n-o ctyl-5-aza-2,8-dioxa-1-stannacyclooctan,
• 1,1-Dibenzoyl- 5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctan,
• 1,1-Bis(p-dodecylphenylsulfonyl)- 5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctan,
• 2-Benzoyloxy-6-octyl-4,8-dioxo-1,3 ,6,2-dioxazastannocan-2-ylbenzoat

oder Mischungen davon.In a further preferred embodiment, one or more of the following compounds are used as the cyclic tin compound:

• 4,12-di-n-butyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-di-n-butyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 2,4,6,10,12,14-hexamethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-di-n-octyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-di-n-octyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 4,12-dimethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro [7.7] pentadecane,
• 1,1-dichloro-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctane,
• 1,1-diisopropyl-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctane,
• 1,1-dibenzoyl-3,3,7,7-tetramethyl 5-noctyl-5-aza-2,8-dioxa-1-stannacyclooctane,
• 1,1-dibenzoyl-5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctane,
• 1,1-bis (p-dodecylphenylsulfonyl) - 5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctane,
• 2-benzoyloxy-6-octyl-4,8-dioxo-1,3,6,2-dioxazastannocan-2-ylbenzoate

or mixtures thereof.

• 4,12-Bis(cyclopentyl)-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol[7.7]pentadecan,
• 4,12-Bis(cyclohexyl)-1,7,9,15 -tetraoxa-4,12-diaza-8-stannaspirol[7.7]pentadecan,
• 4,12-Bis(cyclopentyl)-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol[7.7]pentadecan,
• 4,12-Bis(cyclohexyl)-2,6,10,14-tetramethyl-1,7,9,15 -tetraoxa-4,12-diaza-8-stannaspirol[7.7]pentadecan,
• 4,12-dibutyl-2,6,10,14-tetramethyl-1,7,9,15 -tetraoxa-4,12-diaza-8-stannaspirol [7.7]pentadecan.

Furthermore, preference is given to using at least one or a mixture of at least two of the following compounds as cyclic tin compounds:

• 4,12-bis (cyclopentyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane,
• 4,12-bis (cyclohexyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane,
• 4,12-bis (cyclopentyl) -2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane,
• 4,12-bis (cyclohexyl) -2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane,
• 4,12-dibutyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane.

The construction material in the method according to the invention can, for example, have the following composition, where all figures are in% by weight and the figures in% by weight add up to 100% by weight: NCO-functional urethane acrylate 20-30 Acrylate 35-45 Polyol 30-40 Photoinitiator 1 0.1-0.3 Photoinitiator 2 0.1-0.3 UV inhibitor 0.01-0.3 Sn cat 0.01-0.2

Particularly: NCO-functional urethane acrylate 25.4 Acrylate 39.5 Polyol 34.3 Photoinitiator 1 0.22 Photoinitiator 2 0.22 UV inhibitor 0.2 Sn cat 0.034-0.102

• Acrylat: beispielsweise Isobornylacrylat
• Polyol: beispielsweise ein Polyetherpolyol wie Polytetramethylenetherglycol mit einer Molekülmasse von 1000 g/mol (PolyTHF 1000)
• Photoinitiator 1: Acylphosphinoxid, beispielsweise Ethyl(2,4,6-trimethylbenzoyl)phenylphosphinat (TPOL)
• Photoinitiator 2: Germanium-basierter Photoinitiator wie beispielsweise Bis-4-(methoxybenzoyl)diethy lgerman
• UV-Inhibitor: beispielsweise Mayzo OB+ (2,2'-(2,5-thiophendiyl)bis(5-tertbutylbenzoxazol))
• Sn-Kat: zyklische Zinnverbindung der Formel F-I, F-II oder F-III

NCO-functional urethane acrylate: for example a urethane acrylate which can be obtained from the reaction of trimeric HDI isocyanurate with hydroxypropyl acrylate with an NCO index of 200 by stirring at 60 ° C. until all OH groups have reacted.

• Acrylate: for example isobornyl acrylate
• Polyol: for example a polyether polyol such as polytetramethylene ether glycol with a molecular weight of 1000 g / mol (PolyTHF 1000)
• Photoinitiator 1: acylphosphine oxide, e.g. ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPOL)
• Photoinitiator 2: Germanium-based photoinitiator such as bis-4- (methoxybenzoyl) diethy lgerman
• UV inhibitor: for example Mayzo OB + (2,2 '- (2,5-thiophenediyl) bis (5-tert-butylbenzoxazole))
• Sn-Kat: cyclic tin compound of the formula FI, F-II or F-III

Another object of the present invention is an object obtained by a method according to the invention, the object having a height of 1 1 mm, preferably 5 mm, at least in sections in the construction direction of its manufacturing process.

The invention also relates to the use of cyclic tin compounds of the formula F-I, F-II and / or F-III, as defined in the preceding statements, as thermally latent urethanization catalysts in building materials for additive manufacturing processes.

Experimental part

The invention is explained in more detail with the aid of the following examples, but without being restricted thereto.

The formulations of building materials given in Table 1 containing radical crosslinkable groups, NCO groups and groups with Zerewitinoff-active H atoms were prepared. The data in Table 1 relate to parts by weight.

Example 1 according to the invention:

Build- up material containing Desmodur ® N3390 BA, hydroxyethyl acrylate and 4,12-bis (cyclopentyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane (polyisocyanate with thermolatent catalyst)

Example 2 according to the invention:

Build- up material containing Desmodur ® N3390 BA, hydroxyethyl acrylate and 4,12-bis (cyclohexyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane (polyisocyanate with thermolatent catalyst)

Example 3 according to the invention:

Build- up material containing Desmodur ® N3390 BA, hydroxyethyl acrylate and 4,12-bis (cyclopentyl) -2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane (polyisocyanate with thermolatent catalyst)

Example 4 according to the invention:

Build- up material containing Desmodur ® N3390 BA, hydroxyethyl acrylate and 4,12-bis (cyclohexyl) -2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane (polyisocyanate with thermolatent catalyst)

Example 5 according to the invention:

Build- up material containing Desmodur® N3390 BA, hydroxyethyl acrylate and 4,12-dibutyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirol [7.7] pentadecane (polyisocyanate with thermolatent catalyst)

Comparative example CE 6:

Build- up material containing Desmodur ® N 3390 BA, hydroxyethyl acrylate and dibutyltin dilaurate (DBTL) 400 ppm

Comparative example CE 7:

Build- up material containing Desmodur ® N 3390 BA, hydroxyethyl acrylate and dibutyltin dilaurate (DBTL) 40 ppm

Comparative example CE 8:

Build- up material containing Desmodur ® N 3390 BA, hydroxyethyl acrylate without a catalyst

Desmodur ® N 3390 BA is a commercial product from Covestro AG. The characteristics of Desmodur ® N 3390 BA correspond to the information on the data sheet of the same name in the 2017-06-01 edition. It is an aliphatic polyisocyanate (HDI trimer) approx. 90% strength by weight in n-butyl acetate, which is used, among other things, as a hardener component for lightfast polyurethane paint systems. The NCO content is approx. 19.6% by weight (determined in accordance with DIN EN ISO 11 909), the viscosity at 23 ° C is 500 +/- 150 mPas (determined in accordance with DIN EN ISO 3219 / A.3) . Table 1: Composition of the building materials example 1 2 3 4th 5 VB 6 VB 7 VB 8 Feedstock Parts by weight [%] Desmodur® N 3390 62.93 62.92 62.91 62.90 62.92 63.06 63.096 63.10 4.12-bis (cyclopentyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane 0.17 - - - - - - - 4, 12-bis (cyclohexyl) -1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane - 0.18 - - - - - - 4,12-bis (cyclopentyl) -2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane - - 0.19 - - - - - 4, 12-bis (cyclohexyl) -2,6, 10, 14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane - - - 0.20 - - - - 4, 12-dibutyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspirole [7.7] pentadecane - - - - 0.18 - - - Dibutyltin dilaurate (DBTL) - - - - - 0.04 0.004 - Hydroxyethyl acrylate 34.00 34.00 34.00 34.00 34.00 34.00 34.00 34.00 2-Hydroxy-2-methyl-1-phenyl-propan-1-one 2.90 2.90 2.90 2.90 2.90 2.90 2.90 2.90

Formulation of the building materials:

The components were placed in a plastic beaker with a lid in the order isocyanate (Desmodur® N 3390 BA), catalyst (if used), hydroxyacrylate and the photoinitiator (2-hydroxy-2-methyl-1-phenyl-propan-1-one Omnirad® 1173 from IGM Resins) . These starting materials were mixed in a Thinky ARE250 planetary rotary mixer at room temperature for about 2 minutes at a speed of 2000 revolutions per minute. In all formulations there was a stoichiometric ratio of NCO to OH groups of approx. 1: 1.

Viscosity measurement over the reaction time:

The first viscosity measurement was carried out immediately, i.e. within 2 minutes after mixing for 2 minutes. Further viscosity measurements were then carried out at time intervals, as shown in Table 2. All viscosity measurements which are given in Table 2 were carried out with a viscometer from Anton Paar MCR 51 with a cone-plate measuring system CP25-2 at 23 ° C. Table 2: Viscosity at 23 ° C after different reaction times example 1 2 3 4th 5 VB 6 VB 7 VB 8 time viscosity [Minutes] [mPas] 0 70 70 77 85 78 63,500 55 67 15th nb * nb nb nb 93 70,600 66 150 30th 62 88 80 107 102 polymerized 330 66 60 106 106 113 146 139 - 1,700 66 120 148 146 159 221 222 - 5,700 67 240 323 304 327 563 559 - 15,000 67 1,440 30100 29100 43400 63000 70,000 - polymerized 116 *) nb: not determined

Examples 1 to 5 according to the invention showed a doubling of the initial viscosity, determined at time 0 minutes only after a period of> 60 minutes (pot life).

Comparative example CE 6, containing 400 ppm DBTL, showed a viscosity of 63,000 mPas immediately after mixing and was polymerized after 30 minutes, which is why it was no longer possible to determine the viscosity.

Comparative example CE 7, containing 40 ppm DBTL, showed a doubling of the initial viscosity, determined at time 0 minutes, after less than 30 minutes (pot life).

Comparative example CE 8, without catalyst, showed almost no change in viscosity over 240 minutes.

Film production and infrared measurement of the NCO band:

The free-radically curable building materials according to Examples 1 to 5 according to the invention and Comparative Examples CE 6 to CE 8 were drawn onto a glass plate with a doctor blade with a gap of 400 μm.

The coated glass substrates were then cured in a UV curing system from Superfici with mercury and gallium radiation sources at a belt speed of 5 m / min. The lamp power and belt speed result in a radiation intensity of 1,300 mJ / cm ² , which acted on the coated substrates.

The UV-cured films were then stored on the glass substrates in a drying oven at 150 ° C. under an air atmosphere and removed from the oven at the times listed in Table 3 for the respective IR measurement. After the measurement, the samples were placed back in the oven.

An FT-IR spectrometer ( Tensor II ) from Bruker was used to measure the free NCO groups. The sample film was contacted on the Platinum ATR unit. The contacted area of the sample was 2 × 2 mm. During the measurement, the IR radiation penetrated the sample by 3 to 4 µm, depending on the wave number. An absorption spectrum was then generated from the sample. In order to compensate for an uneven contact of the samples with different hardnesses, a baseline correction and a normalization in the wave number range from 2600 to 3200 (CH2, CH3) were carried out on all spectra. The integration of the signal of the NCO groups (called “Integral NCO” in Table 3) was carried out in the wavenumber range from 2170 to 2380. For the build-up material without catalyst according to Comparative Example CE 8, a numerical value of 510 was obtained after exposure, while a completely reacted film had a numerical value of 0. As a result, the aim was to achieve a conversion of> 70% of the isocyanate groups within 1 hour of post-curing. The NCO conversion was assumed for the consideration as a linear function of the height of the area peak. The initial value of comparative example CE 8 was defined as 0% conversion. Table 3: “Integral NCO” after UV curing and storage at 150 ° C example 1 2 3 4th 5 6th 7th 8th Time [minutes] Integral NCO (sales [%]) 0 491.9 (4) 504.2 (1) 498.1 (2) 492.8 (3) 503.0 (1) 50.0 (90) 471.0 (8) 510.0 (0) 30th 143.4 (72) 127.6 (75) 128.5 (75) 58.3 (89) 129.0 (75) 29.0 (94) 347.0 (32) 488.0 (4) 60 105.6 (79) 101.2 (80) 87.2 (83) 65.8 (87) 102.0 (80) 41.0 (92) 290.0 (43) 358.0 (30) 240 53.1 (90) 49.0 (90) 45.8 (91) 32.3 (94) 76.0 (85) 13.0 (97) 182.0 (64) 261.0 (49) 1,440 26.9 (95) 34.1 (93) 25.5 (95) 22.1 (96) 14.0 (97) 11.0 (98) 29.0 (94) 76.0 (85)

Examples 1 to 5 according to the invention showed a significantly more rapid degradation of the NCO integral than comparative examples CE 6 and CE 7, containing 400 and 40 ppm DBTL, respectively. Whereas for all examples according to the invention a conversion of the NCO groups of 72 72% already took place after storage for 30 minutes at 150 ° C., in comparative example CE 7, containing 40 ppm DBTL, only 32% of the NCO groups reacted. After 60 minutes, the NCO conversion for the examples according to the invention is 79%, while for comparative example CE 7 the NCO conversion is only 43%.

Comparative example CE 6, containing 400 ppm DBTL, showed immediately after UV curing a very low NCO integral of 50.0, which corresponded to a conversion of 90% of the NCO groups. This is due to a reaction of many isocyanate groups already during the UV exposure and the sample preparation for the infrared measurement, due to the high amount of DBTL. This is also confirmed by the viscosity measurements shown above after different reaction times at 23 ° C.

Comparative Example CE 8, without a catalyst, also showed a decrease in the NCO integral over time, but significantly more slowly than in the case of the catalyzed systems. Only after 240 minutes had about half of the NCO groups reacted during storage at 150 ° C.

In summary, the building materials according to Examples 1 to 5 according to the invention, containing a latently reactive catalyst, showed a significantly longer pot life than the building materials catalyzed with DBTL according to Comparative Examples CE 6 and CE 7. At the same time, the building materials according to the invention reacted significantly faster (NCO-OH reaction). during storage at 150 ° C as a build-up material without a catalyst, such as DBTL, with a long pot life according to Comparative Example CE 8. This combination of properties thus demonstrates the desired heat-latent effect of the catalysts compared to the conventional catalysis of the NCO-OH reaction by means of DBTL and shows due to the sufficiently long pot life with fast reaction when heated, a very good suitability for use in formulations, such as is desired in 3D printing or in paint and adhesive applications.

Claims (15)

1. Process for producing an article made of a build material, wherein the build material comprises free-radically crosslinkable groups, NCO groups and groups having Zerewitinoff-active H atoms and the article is a three-dimensional article and/or a layer,
   characterized in that
   during and/or after production of the article the build material is heated to a temperature of ≥ 50°C and in that the build material comprises one or more cyclic tin compounds of formula F-I, F-II and/or F-III:

   

   

   

   wherein:

   D represents -O-, -S- or -N(R1)-
   wherein R1 represents a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic radical or an optionally substituted aromatic or araliphatic radical which has up to 20 carbon atoms and may optionally contain heteroatoms from the group of oxygen, sulfur, nitrogen, or is hydrogen or the radical

   

   or R1 and L3 together represent -Z-L5-;

   D* represents -O- or -S-;

   X, Y and Z represent identical or different radicals selected from alkylene radicals of formulae -C(R2)(R3)-, -C(R2)(R3)-C(R4)(R5)- or -C(R2)(R3)-C(R4)(R5)-C(R6)(R7)- or ortho-arylene radicals of formulae

   

   or

   

   wherein R2 to R11 independently represent saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or optionally substituted aromatic or araliphatic radicals which have up to 20 carbon atoms and may optionally contain heteroatoms from the group of oxygen, sulfur, nitrogen, or are hydrogen; L1, L2 and L5 independently represent -O-, -S-, -OC(=O)--OC(=S)-, -SC(=O)-, -SC(=S)-, -OS(=O)₂O-, -OS(=O)₂- or -N(R12)-,
   wherein R12 represents a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic radical or an optionally substituted aromatic or araliphatic radical which has up to 20 carbon atoms and may optionally contain heteroatoms from the group of oxygen, sulfur, nitrogen, or is hydrogen;

   L3 and L4 independently represent -OH, -SH, -OR13, -Hal, -OC(=O)R14, -SR15, -OC(=S)R16, -OS(=O)₂OR17, -OS(=O)₂R18 or -NR19R20, or L3 and L4 together represent -L1-X-D-Y-L2-,

   wherein R13 to R20 independently represent saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or optionally substituted aromatic or araliphatic radicals which have up to 20 carbon atoms and may optionally contain heteroatoms from the group of oxygen, sulfur, nitrogen, or are hydrogen.
2. Process according to Claim 1, characterized in that the article is a three-dimensional article and is obtained from a precursor and in that the process comprises the steps of:

   I) depositing free-radically crosslinked build material atop a carrier to obtain a ply of a build material joined to the carrier which corresponds to a first selected cross section of the precursor;

   II) depositing free-radically crosslinked build material atop a previously applied ply of the build material to obtain a further ply of the build material which corresponds to a further selected cross section of the precursor and which is joined to the previously applied ply;

   III) repeating step II) until the precursor is formed;

   wherein the depositing of free-radically crosslinked build material at least in step II) is effected by exposure and/or irradiation of a selected region of a free-radically crosslinkable build material corresponding to the respectively selected cross section of the precursor and
   wherein the free-radically crosslinkable build material has a viscosity (23°C, DIN EN ISO 2884-1) of ≥ 5 mPas to ≤ 1 000 000 mPas,
   wherein the free-radically crosslinkable build material comprises a curable component comprising NCO groups and olefinic C=C double bonds,
   and in that step III) is followed by a further step IV):
   IV) heating the precursor obtained after step III) to a temperature of ≥ 50°C to obtain the article.
3. Process according to Claim 2, characterized in that:

   - the carrier is arranged inside a container and is vertically lowerable in the direction of the gravitational force,

   - the container contains the free-radically crosslinkable build material in an amount sufficient to cover at least the carrier and an uppermost surface of crosslinked build material deposited on the carrier as viewed in the vertical direction,

   - before each step II) the carrier is lowered by a predetermined distance so that above the uppermost ply of the crosslinked build material viewed in the vertical direction a layer of the free-radically crosslinkable build material is formed and

   - in step II) an energy beam exposes and/or irradiates the selected region of the layer of the free-radically crosslinkable build material corresponding to the respectively selected cross section of the precursor.
4. Process according to Claim 2, characterized in that:

   - the carrier is arranged inside a container and is vertically raisable counter to the direction of the gravitational force,

   - the container provides the free-radically crosslinkable build material,

   - before each step II) the carrier is raised by a predetermined distance so that below the lowermost ply of the crosslinked build material viewed in the vertical direction a layer of the free-radically crosslinkable build material is formed and

   - in step II) a plurality of energy beams simultaneously exposes and/or irradiates the selected region of the layer of the free-radically crosslinkable build material corresponding to the respectively selected cross section of the precursor.
5. Process according to Claim 2, characterized in that:

   - in step II) the free-radically crosslinkable build material is applied from one or more printing heads corresponding to the respectively selected cross section of the precursor and is subsequently exposed and/or irradiated.
6. Process according to Claim 1, characterized in that the article is a coating and the process comprises the steps of:

   - applying the build material atop a substrate

   - heating and/or UV-irradiating the applied build material to effect in the applied build material an at least partial crosslinking of the free-radically crosslinkable groups

   - heating the applied build material to a temperature of ≥ 50 °C to effect in the applied build material at least in part a reaction between NCO groups and groups having Zerewitinoff-active H atoms.
7. Process according to Claim 1, characterized in that the article is an adhesive bond and the process comprises the steps of:

   - applying the build material atop a first substrate

   - contacting the applied build material with a second substrate

   - heating and/or UV-irradiating the applied build material to effect in the applied build material an at least partial crosslinking of the free-radically crosslinkable groups

   - heating the applied build material to a temperature of ≥ 50 °C to effect in the applied build material at least in part a reaction between NCO groups and groups having Zerewitinoff-active H atoms.
8. Process according to any of Claims 1 to 7, characterized in that the build material further comprises a free-radical starter and/or an isocyanate trimerization catalyst.
9. Process according to any of Claims 1 to 8, characterized in that the build material is obtained by mixing an NCO-containing component and a component containing groups having Zerewitinoff-active H atoms and the mixing is effected ≤ 5 minutes before commencement of the process.
10. Process according to any of Claims 1 to 9, characterized in that in the definition according to Claim 1 D is -N(R1)- and R1 is hydrogen or an alkyl, aralkyl, alkaryl or aryl radical having up to 20 carbon atoms or the radical

    
11. Process according to any of Claims 1 to 10, wherein in the definition according to Claim 1 R1 is hydrogen or a methyl, ethyl, propyl, butyl, hexyl, octyl, Ph, or CH₃Ph radical or the radical

    

    and wherein propyl, butyl, hexyl and octyl represent all isomeric propyl, butyl, hexyl and octyl radicals.
12. Process according to any of Claims 1 to 11, characterized in that in the definition according to Claim 1 D* is -O-.
13. Process according to any of Claims 1 to 12, characterized in that as the cyclic tin compound one or more of the following compounds are employed:

    4,12-di-n-butyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    4,12-di-n-butyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    2,4,6,10,12,14-hexamethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    4,12-di-n-octyl-2,6,10,14-tetramethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    4,12-di-n-octyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    4,12-dimethyl-1,7,9,15-tetraoxa-4,12-diaza-8-stannaspiro[7.7]pentadecane,

    1,1-dichloro-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctane,

    1,1-diisopropyl-5-methyl-5-aza-2,8-dioxa-1-stannacyclooctane,

    1,1-dibenzoyl-3,3,7,7-tetramethyl 5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctane,

    1,1-dibénzoyl-5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctane,

    1,1-bis(p-dodecylphenylsulfonyl)-5-n-octyl-5-aza-2,8-dioxa-1-stannacyclooctane,

    2-benzoyloxy-6-octyl-4,8-dioxo-1,3,6,2-dioxazastannocan-2-yl benzoate

    or mixtures thereof.
14. Article obtained by a process according to any of Claims 1 to 13, characterized in that in the build direction of its production process at least in sections the article has a height of ≥ 1 mm.
15. Use of cyclic tin compounds of formula F-I, F-II and/or F-III as defined in Claim 1, 10, 11, 12 or 13 as thermally latent urethanization catalysts in build materials in additive manufacturing processes.